fix: mappings/VegCore-VegBIEN.csv: taxonoccurrence.sourceaccessioncode: need to populate from aggregateOrganismObservationID when only that is available

moved everything into /trunk/ to create the standard svn layout, for use with tools that require this (eg. git-svn). IMPORTANT: do NOT do an `svn up`. instead, re-use your working copy's existing files with `svn switch` (http://svnbook.red-bean.com/en/1.6/svn.ref.svn.c.switch.html).

fix: bin/map: put template: comment out the "Put template:" label so that the output is valid XML, and displays properly in a browser rather than showing a syntax error

bugfix: mappings/VegCore-VegBIEN.csv: nest all taxonoccurrences inside a stratum event, so that the parent locationevent is always fully populated before child locationevents point to it. (previously, a stub parent event was created when the child event was imported first, which blocked the fully-populated parent event from being inserted later on.) this uses auto-folding (for VegBank/CVS) and auto-forwarding (for other datasources) to prune empty stratum events for taxonoccurrences that don't have strata. (see wiki.vegpath.org/Auto-folding, wiki.vegpath.org/Auto-forwarding for more info about these normalization techniques.) note that the inserted row counts stay exactly the same for all datasources except VegBank (which was being fixed), indicating that this signficant change to the mappings did not change the semantics of the import of taxonoccurrences.

bugfix: inputs/VegBank/: taxonOccurrenceID: include the aggregateOrganismObservationID in this so that there is one taxonoccurrence for each stratum's taxonImportance. this allows the different strata to have separate taxonoccurrences that are associated with the stratum-specific locationevents, rather than all being lumped into one taxonoccurrence, with only one locationevent.

inputs/VegBank/stemcount_/map.csv: stratum_id: removed table prefix so it can be used as a join column

inputs//: don't import joined tables, because they are now imported in the taxon_observation.** left-join instead

inputs/VegBank/stemcount_/postprocess.sql: moved stemcount___parent index before the derived columns section because it does not depend on them

bugfix: inputs/VegBank/stemcount_/postprocess.sql: added missing index on taxonOccurrenceID, needed for the 1:many portion of the taxon_observation.** left-join

inputs/VegBank/stemcount_/postprocess.sql: added primary key. note that the inserted row count changes, most likely because the rows are now in sorted order.